1. Field of the Invention
The present invention relates to colorants comprising certain cationic quinoxaline thiazole azo dyes for keratin fibers, such as, for example, hair, wool or furs.
2. Description of Related Art
In general, to color keratin-containing fibers, use is made either of oxidation dyes, which arise as a result of oxidative coupling or one or more developer components with one or more coupler components, or direct dyes. If required, oxidation-stable, direct dyes can be added to the oxidative system in order to achieve particular color effects. Direct dyes are incorporated into suitable carrier masses in order then to be applied to the fibers. This method, generally known as tinting, is easy to use, exceptionally mild and is characterized by low damage to the keratin fibers since no ammonia or peroxide is added. However, the dyes used here have to satisfy a number of requirements. For example, they have to be acceptable from a toxicological and dermatological point of view and allow colorations to be achieved in a desired intensity and brilliance. Furthermore, the colorations achieved also have to have good fastness to light and resistance to shampoos or hair care products, and good fastness to rubbing.
For a direct, nonoxidative colorant for keratin fibers, a combination of different nonoxidative dyes is generally required in order to achieve certain nuances.
Since the choice of such dyes which adequately satisfy the specified requirements is limited, there continues to be a great need for such dyes.
A further, very interesting field of use for direct dyes is their use in products for simultaneous lightening and coloring. In the case of these colorants, which may have a higher content of oxidizing agents, even further-reaching requirements are placed on the dyes used, particularly with regard to adequate resistance to the oxidizing agents used.
To date, there are hardly any dyes which satisfy the abovementioned prerequisites in every respect and at the same time produce a satisfactory color result. It is therefore an object of the present invention to provide direct dyes for coloring keratin fibers, in particular human hair, which satisfy these requirements.